Getting a high gloss finish using epoxy can be difficult and most surf how to sites do not suggest epoxy. However we came across this novel method in a woodworking section. We are going to try this with masts and wings.

See DIY- How to apply "Liquid Glass" Epoxy Resin on almost any surface.

Yes, and I've stopped putting gloss finish on my kitesurfboards. It's a lot of work, adds weight, is more susceptible to cosmetic damage, you see cosmetic damage easier, and it's very slippery to hold when wet. I actually think the Matt finish is more attractive.

I think you mean additive F. I've tried it and had problems that seem to be systematic, others have similar problem. Then I started using XCR coating epoxy front easycomposites in UK. This is excellent coating epoxy with very good flow out, bubble reduction and absolutely no amine blush. Way better than resin research with additive F.
Still work, weight and results are not worth it to me. Some people like the glossy look though.

Have always fought with air bubbles in epoxy filler coats, a pain to sand out once cured. I tried the micro torch last night, worked a treat. Agree that gloss finishes aren't the go, but it is food for filler coats, I used a brush to apply

For an almost gloss finish most pros use wipe-on acrylic floor sealer over a well sanded finish, 300 400 600 grit or whatever.
For a really glossy finish most spray acrylic over same.
Purists/masochists go for the buffing wheel and compound etc.

not that much of a problem to get a perfect finish coat. Every coat will only be as good as the one before, so put down a nice clean sanding coat, sand it perfect with a 80 grit, brush dust off, clean it with DNA wait 10 minutes and put your finish coat with a foam brush on.
Temperature is very important, always do finish coats in a clean room with falling temperatures, if temps raise during curing you will get bubbles.
Use the fastest hardener you can get, Sicomin EVO with Super Fast hardener works great. Then sand with 600 800 1000 1200 machine wet sanding and polish as shiny as you like.